阅读说明：本技术 混合动力车辆和控制混合动力车辆的方法 (Hybrid vehicle and method of controlling hybrid vehicle ) 是由 米泽幸一 吉嵜聪 前田治 安藤大吾 浅见良和 板垣宪治 尾山俊介 牟田浩一郎 于 2020-03-24 设计创作，主要内容包括：本发明涉及混合动力车辆和控制混合动力车辆的方法。HV-ECU执行如下处理,该处理包括：计算要求的系统功率(S100),当已经发出发动机启动要求时(在S102中为是),计算要求发动机功率(S104),在预定运行线上设定运行点(S106),当车辆处于运动行驶状态下时(S108中为是)且当先前的运行点在增压进气区域内时(在S110中为是),将发动机转速的降低量的大小的上限值设定为第一值(S112),当车辆不处于运动行驶状态下时(S108中为否)或当先前的运行点不在增压进气区域内时(在S110中为否),将上限值设定为第二值(S114),校正运行点(S116),并且输出发动机运行状态指令、第一MG扭矩指令及第二MG扭矩指令(S118、S120和S120)。(The invention relates to a hybrid vehicle and a method of controlling the hybrid vehicle. The HV-ECU executes processing including: calculating a required system power (S100), when an engine start request has been issued (yes in S102), calculating a required engine power (S104), setting an operating point on a predetermined operating line (S106), when the vehicle is in a moving running state (yes in S108) and when a previous operating point is within a supercharged intake region (yes in S110), setting an upper limit value of a magnitude of a reduction amount of an engine rotational speed to a first value (S112), when the vehicle is not in a moving running state (no in S108) or when the previous operating point is not within the supercharged intake region (no in S110), setting the upper limit value to a second value (S114), correcting the operating point (S116), and outputting an engine operating state command, a first MG torque command, and a second MG torque command (S118, S120, and S120).)

1. A hybrid vehicle comprising:

an engine including a boosted air intake;

a motor generator that generates electricity by using power of the engine;

a power splitter that splits power output from the engine into power to be transmitted to the motor generator and power to be transmitted to drive wheels; and

a controller that sets an operating point at which a required engine power of the engine is output, and that controls the engine and the motor generator to reach the set operating point, wherein:

the controller sets an upper limit value of a magnitude of change per prescribed period of the operating point to be smaller when the required engine power is reduced in a supercharged intake region in which a supercharged intake operation is performed by the supercharged intake means than when the required engine power is reduced in a non-supercharged intake region.

2. The hybrid vehicle according to claim 1, wherein:

when the required engine power is reduced in the supercharged intake region, the controller sets the upper limit value of the magnitude of reduction in engine speed per prescribed period to be smaller than the upper limit value of the magnitude of reduction in engine speed per prescribed period when the required engine power is reduced in the non-supercharged intake region.

3. The hybrid vehicle according to claim 1 or 2, wherein:

when the required engine power is reduced in the supercharged intake region while the vehicle is in a running state, the controller sets the upper limit value of the magnitude of change per prescribed period of the operating point to be smaller than the upper limit value of the magnitude of change per prescribed period of the operating point when the required engine power is reduced in the non-supercharged intake region.

4. A method of controlling a hybrid vehicle, the hybrid vehicle comprising: an engine including a boosted air intake; a motor generator that generates electricity by using power of the engine; and a power splitter that splits power output from the engine into power to be transmitted to the motor generator and power to be transmitted to drive wheels, the method comprising:

setting an operating point at which a required engine power of the engine is output, and controlling the engine and the motor generator to reach the set operating point; and

when the required engine power is reduced in a supercharged intake region in which a supercharged intake operation is performed by the supercharged intake means, the upper limit value of the magnitude of change per prescribed period of the operating point is set smaller than the upper limit value of the magnitude of change per prescribed period of the operating point when the required engine power is reduced in a non-supercharged intake region.

Technical Field

The present disclosure relates to control of a hybrid vehicle including an electric motor and an engine including a supercharged intake device as drive sources.

Background

There has conventionally been known a hybrid vehicle that includes an electric motor and an engine as drive sources, includes an electric power storage that is charged using power of the engine, and runs with the power of the engine. Some engines mounted on such hybrid vehicles include a supercharged intake device such as a turbocharger.

For example, japanese patent laid-open No. 2015-58924 discloses a hybrid vehicle that includes an electric motor and an engine that includes a turbocharger.

Disclosure of Invention

In the above-described hybrid vehicle, when the operation of closing the accelerator is performed using the power of the engine during running of the vehicle, the power required by the engine is reduced or the engine is stopped in response to the operation performed by the user from the viewpoint of improving the fuel efficiency. However, when the operation of opening the accelerator is performed again within a short time after the operation of closing the accelerator, acceleration lag may be caused due to a delay in response of the boost pressure. In particular, in the hybrid vehicle, as described above, the engine may also be stopped by the operation of closing the accelerator. Therefore, when the operation of opening the accelerator is performed in a short time after the operation of closing the accelerator, a delay in acceleration may occur more significantly. Therefore, the drivability of the vehicle may be deteriorated.

An object of the present disclosure is to provide a hybrid vehicle that achieves suppression of occurrence of acceleration lag due to a response delay of a boost pressure, and a method of controlling the hybrid vehicle.

A hybrid vehicle according to an aspect of the present disclosure includes: an engine including a boosted air intake; a motor generator that generates electricity by using power of an engine; a power splitter that splits power output from the engine into power to be transmitted to the motor generator and power to be transmitted to drive wheels; and a controller that sets an operating point at which a required engine power of the engine is output, and controls the engine and the motor generator to reach the set operating point. When the required engine power is reduced in the supercharged intake region in which the supercharged intake operation is performed by the supercharged intake means, the controller sets the upper limit value of the magnitude of change per prescribed period of the operating point to be smaller than the upper limit value of the magnitude of change per prescribed period of the operating point when the required engine power is reduced in the non-supercharged intake region.

By so doing, for example, even when an operation to open the accelerator is performed within a short period of time after the operation to close the accelerator in the supercharged intake region, the change in the operating point is slower than in the non-supercharged intake region. Therefore, the supercharging pressure can be maintained, and a quick stop of the engine can be suppressed. Therefore, it is possible to suppress the occurrence of acceleration lag due to a response delay of the boost pressure. Therefore, deterioration of the drivability of the vehicle can be suppressed.

In one embodiment, when the requested engine power is reduced in the supercharged intake region, the controller sets the upper limit value of the magnitude of the reduction amount of the engine speed per a prescribed period to be smaller than the upper limit value of the magnitude of the reduction amount of the engine speed per a prescribed period when the requested engine power is reduced in the non-supercharged intake region.

By so doing, for example, even when an operation to open the accelerator is performed within a short period of time after the accelerator operation, the change in the engine speed is slow, so the boost pressure can be maintained. Therefore, it is possible to suppress the occurrence of acceleration lag due to a response delay of the boost pressure.

Further, in one embodiment, when the required engine power is reduced in the supercharged intake region while the vehicle is in the moving running state, the controller sets the upper limit value of the magnitude of change per prescribed period of the operating point to be smaller than the upper limit value of the magnitude of change per prescribed period of the operating point when the required engine power is reduced in the non-supercharged intake region.

By so doing, when the operation to turn on the accelerator is performed within a short period of time after the operation to turn off the accelerator while the vehicle is in a sport running state where the fuel efficiency is not regarded as important to the user, it is possible to suppress the occurrence of acceleration lag due to a response delay of the boost pressure. Therefore, deterioration of the drivability of the vehicle in the moving running state can be suppressed.

A method of controlling a hybrid vehicle according to another aspect of the present disclosure is a method of controlling a hybrid vehicle including: an engine including a boosted air intake; a motor generator that generates electricity by using power of an engine; and a power splitter that splits power output from the engine into power to be transmitted to the motor generator and power to be transmitted to the drive wheels. The method comprises the following steps: setting an operating point at which a required engine power of the engine is output, and controlling the engine and the motor generator to reach the set operating point; and setting an upper limit value of a magnitude of change per prescribed period of the operating point to be smaller than an upper limit value of a magnitude of change per prescribed period of the operating point when the required engine power is reduced in a non-supercharged intake region in which a supercharged intake operation is performed by the supercharged intake means, when the required engine power is reduced in the supercharged intake region.

The foregoing and other objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when considered in conjunction with the accompanying drawings.

Drawings

Fig. 1 is a diagram showing an exemplary configuration of a drive system of a hybrid vehicle.

Fig. 2 is a diagram showing an exemplary configuration of an engine including a turbocharger.

Fig. 3 is a block diagram showing an exemplary configuration of the controller.

Fig. 4 is a flowchart showing an exemplary process executed by the HV-ECU.

Fig. 5 is a diagram for explaining an exemplary operation of the HV-ECU.

Detailed Description

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The same or corresponding elements in the drawings have the same reference numerals assigned thereto, and the description thereof will not be repeated.

< drive System for hybrid vehicle >

Fig. 1 is a diagram showing an exemplary configuration of a drive system of a hybrid vehicle (hereinafter simply referred to as a vehicle) 10. As shown in fig. 1, a vehicle 10 includes a controller 11 as a drive system, and an engine 13, a first motor generator (hereinafter, referred to as a first MG)14, and a second motor generator (hereinafter, referred to as a second MG)15, which serve as power sources for running. The engine 13 includes a turbocharger 47. The first MG14 and the second MG 15 each perform a function as a motor that outputs torque by being supplied with driving electric power and a function as a generator that generates electric power by being supplied with torque. For the first MG14 and the second MG 15, an Alternating Current (AC) rotating electric machine is employed. The alternating-current rotary electric machine includes, for example, a permanent magnet synchronous motor including a rotor in which permanent magnets are embedded.

The first MG14 and the second MG 15 are electrically connected to the battery 18 with a Power Control Unit (PCU)81 interposed between the first MG14 and the second MG 15 and the battery 18. The PCU81 includes: a first inverter 16 that supplies electric power to the first MG14 and receives electric power from the first MG 14; a second inverter 17 that supplies electric power to the second MG 15 and receives electric power from the second MG 15; a battery 18; and a converter 83, the converter 83 supplying power to the first inverter 16 and the second inverter 17 and receiving power from the first inverter 16 and the second inverter 17.

For example, the converter 83 may boost-convert the electric power from the battery 18 and supply the boost-converted electric power to the first inverter 16 or the second inverter 17. Alternatively, the converter 83 may down-convert the electric power supplied from the first inverter 16 or the second inverter 17 and supply the down-converted electric power to the battery 18.

The first inverter 16 may convert Direct Current (DC) power from the converter 83 into alternating current power, and supply the alternating current power to the first MG 14. Alternatively, the first inverter 16 may convert the alternating-current power from the first MG14 into direct-current power and supply the direct-current power to the converter 83.

The second inverter 17 may convert the direct-current power from the converter 83 into alternating-current power, and supply the alternating-current power to the second MG 15. Alternatively, the second inverter 17 may convert the alternating-current power from the second MG 15 into direct-current power and supply the direct-current power to the converter 83.

The PCU81 charges the battery 18 with electric power generated by the first MG14 or the second MG 15, or drives the first MG14 or the second MG 15 with electric power from the battery 18.

The battery 18 includes, for example, a lithium-ion secondary battery or a nickel metal hydride secondary battery. The lithium ion secondary battery is a secondary battery using lithium as a charge carrier, and may include not only a general lithium ion secondary battery including a liquid electrolyte but also a so-called all-solid-state battery including a solid electrolyte. The battery 18 should be only an at least rechargeable power storage, and an electric double layer capacitor may be used instead of the secondary battery, for example.

The engine 13 and the first MG14 are coupled to the planetary gear mechanism 20. The planetary gear mechanism 20 transmits the drive torque output from the engine 13 by dividing the drive torque into the drive torque of the first MG14 and the drive torque of the output gear 21, and represents an exemplary power splitter in the embodiment of the present disclosure. The planetary gear mechanism 20 includes a single pinion planetary gear mechanism, and is arranged on an axis Cnt coaxial with an output shaft 22 of the engine 13.

The planetary gear mechanism 20 includes a sun gear S, a ring gear R provided coaxially with the sun gear S, pinion gears P meshing with the sun gear S and the ring gear R, and a carrier C holding the pinion gears P rotatably and revolvably. The output shaft 22 is coupled to the carrier C. The rotor shaft 23 of the first MG14 is coupled to the sun gear S. The ring gear R is coupled to the output gear 21. The output gear 21 represents one of output elements for transmitting the driving torque to the driving wheels 24.

In the planetary gear mechanism 20, a carrier C is used as an input element, to which a drive torque output from the engine 13 is transmitted, a ring gear R that outputs the drive torque to the output gear 21 is used as an output element, and a sun gear S (to which the rotor shaft 23 is coupled) is used as a reaction force element. The planetary gear mechanism 20 divides the power output from the engine 13 into power on the first MG14 side and power on the output gear 21 side. The first MG14 is controlled to output torque in accordance with the engine speed.

The intermediate shaft 25 is arranged parallel to the axis Cnt. The intermediate shaft 25 is attached to a driven gear 26 that meshes with the output gear 21. Attached to the counter shaft 25 is a drive gear 27, which drive gear 27 meshes with a ring gear 29 in a differential gear 28 as a final reduction gear. A drive gear 31 attached to a rotor shaft 30 in the second MG 15 meshes with the driven gear 26. Therefore, the drive torque output from the second MG 15 is added to the drive torque output from the output gear 21 in a part of the driven gear 26. The thus combined drive torque is transmitted to the drive wheels 24 with the drive shaft 32 and the drive shaft 33 extending laterally from the differential gear 28, the differential gear 28 being interposed between the drive shaft 32 and the drive shaft 33. When the driving torque is transmitted to the driving wheels 24, a driving force is generated in the vehicle 10.

A mechanical oil pump (hereinafter referred to as MOP)36 is provided coaxially with the output shaft 22. The MOP36 delivers lubricating oil having a cooling function, for example, to the planetary gear mechanism 20, the first MG14, the second MG 15, and the differential gear 28. The vehicle 10 also includes an electric oil pump (hereinafter EOP) 38. When the engine 13 stops operating, the EOP38 is driven by electric power supplied from the battery 18 and delivers lubricating oil to the planetary gear mechanism 20, the first MG14, the second MG 15, and the differential gear 28 in the same or similar manner as the MOP 36.

< construction of Engine >

Fig. 2 is a diagram showing an exemplary configuration of the engine 13 including the turbocharger 47. The engine 13 is, for example, an in-line four-cylinder spark ignition internal combustion engine. As shown in fig. 2, the engine 13 includes, for example, an engine main body 40, and the engine main body 40 is formed with four cylinders 40a, 40b, 40c, and 40d aligned in one direction.

One end of an intake port and one end of an exhaust port formed in the engine body 40 are connected to the cylinders 40a, 40b, 40c, and 40 d. One end of the intake port is opened and closed by two intake valves 43 provided in each of the cylinders 40a, 40b, 40c, and 40d, and one end of the exhaust port is opened and closed by two exhaust valves 44 provided in each of the cylinders 40a, 40b, 40c, and 40 d. The other ends of the intake ports of the cylinders 40a, 40b, 40c, and 40d are connected to an intake manifold 46. The other ends of the exhaust ports of the cylinders 40a, 40b, 40c, and 40d are connected to an exhaust manifold 52.

In the present embodiment, the engine 13 is, for example, a direct injection engine, and fuel is injected into each of the cylinders 40a, 40b, 40c, and 40d through a fuel injector (not shown) provided at the top of each cylinder. The air-fuel mixture of the fuel and the intake air in the cylinders 40a, 40b, 40c, and 40d is ignited by the ignition plug 45 provided in each of the cylinders 40a, 40b, 40c, and 40 d.

Fig. 2 shows the intake valve 43, the exhaust valve 44, and the ignition plug 45 provided in the cylinder 40a, and does not show the intake valve 43, the exhaust valve 44, and the ignition plug 45 provided in the other cylinders 40b, 40c, and 40 d.

The engine 13 is provided with a turbocharger 47, and the turbocharger 47 supercharges the intake air using the energy of exhaust gas. The turbocharger 47 includes a compressor 48 and a turbine 53.

The intake passage 41 has one end connected to an intake manifold 46 and the other end connected to an intake port. The compressor 48 is provided at a prescribed position in the intake passage 41. An air flow meter 50 is provided between the other end (intake port) of the intake passage 41 and the compressor 48, and the air flow meter 50 outputs a signal to the controller 11 according to the flow rate of air flowing through the intake passage 41. An intercooler 51 is disposed in the intake passage 41 provided downstream of the compressor 48, and the intercooler 51 cools the intake air pressurized by the compressor 48. An intake throttle valve (throttle valve) 49 is provided between the intercooler 51 and one end of the intake passage 41, and the intake throttle valve 49 is capable of adjusting the flow rate of intake air flowing through the intake passage 41.

The exhaust passage 42 has one end connected to the exhaust manifold 52 and the other end connected to a muffler (not shown). The turbine 53 is provided at a prescribed position in the exhaust passage 42. When the turbine 53 is started by the exhaust gas, the compressor 48 is started in cooperation with the turbine 53. Intake air drawn through the intake is pressurized as a result of the activation of the compressor 48.

In the exhaust passage 42, a bypass passage 54 that bypasses the exhaust gas upstream of the turbine 53 to a portion downstream of the turbine 53, and a wastegate valve 55 that is provided in the bypass passage 55 and is capable of adjusting the flow rate of the exhaust gas guided to the bypass passage 54 are provided. Therefore, the flow rate of the exhaust gas flowing into the turbine 53 (i.e., the boost pressure of the intake air) is adjusted by controlling the position of the wastegate valve 55.

The exhaust gas passing through the turbine 53 or the wastegate valve 55 is purified by a startup converter 56 and an aftertreatment device 57 provided at prescribed positions in the exhaust passage 42, and then discharged into the atmosphere. The aftertreatment device 57 contains, for example, a three-way catalyst.

The engine 13 is provided with an Exhaust Gas Recirculation (EGR) device 58, and the EGR device 58 causes exhaust gas to flow into the intake passage 41. The EGR device 58 includes an EGR passage 59, an EGR valve 60, and an EGR cooler 61. The EGR passage 59 allows some of the exhaust gas to be discharged as EGR gas from the exhaust passage 42, and guides the EGR gas to the intake passage 41. The EGR valve 60 adjusts the flow rate of EGR gas flowing through the EGR passage 59. The EGR cooler 61 cools the EGR gas flowing through the EGR passage 59. The EGR passage 59 connects a portion of the exhaust passage 42 between the start-up converter 56 and the aftertreatment device 57 to a portion of the intake passage 41 between the compressor 48 and the airflow meter 50.

< construction of controller >

Fig. 3 is a block diagram showing an exemplary configuration of the controller 11. As shown in fig. 3, the controller 11 includes a Hybrid Vehicle (HV) -Electronic Control Unit (ECU)62, an MG-ECU 63, and an engine ECU 64.

The HV-ECU62 is a controller that coordinately controls the engine 13, the first MG14, and the second MG 15. The MG-ECU 63 is a controller that controls the operation of the PCU 81. The engine ECU 64 is a controller that controls the operation of the engine 13.

The HV-ECU62, the MG-ECU 63, and the engine ECU 64 each include: input and output devices that supply signals to and receive signals from various sensors and other ECUs connected thereto; a memory for storing various control programs or maps (including a Read Only Memory (ROM) and a Random Access Memory (RAM)); a Central Processing Unit (CPU) that executes a control program; and a timer that times.

A vehicle speed sensor 66, an accelerator position sensor 67, a first MG rotational speed sensor 68, a second MG rotational speed sensor 69, an engine rotational speed sensor 70, a turbine rotational speed sensor 71, a boost pressure sensor 72, a battery monitoring unit 73, a first MG temperature sensor 74, a second MG temperature sensor 75, a first INV temperature sensor 76, a second INV temperature sensor 77, a catalyst temperature sensor 78, a turbine temperature sensor 79, a sport mode selection switch 90, a brake pedal stroke sensor 91, a steering angle sensor 92, a G sensor 93, and the air flow meter 50 are connected to the HV-ECU 62.

The vehicle speed sensor 66 detects the speed of the vehicle 10 (vehicle speed). The accelerator position sensor 67 detects the depression amount of the accelerator pedal (accelerator position). The first MG rotation speed sensor 68 detects the rotation speed of the first MG 14. The second MG rotation speed sensor 69 detects the rotation speed of the second MG 15. The engine speed sensor 70 detects the rotational speed of the output shaft 22 of the engine 13 (engine speed). The turbine rotation speed sensor 71 detects the rotation speed of the turbine 53 of the turbocharger 47. The boost pressure sensor 72 detects the boost pressure of the engine 13. The first MG temperature sensor 74 detects an internal temperature of the first MG14, such as a temperature associated with a coil or a magnet. The second MG temperature sensor 75 detects the internal temperature of the second MG 15, such as the temperature associated with a coil or a magnet. The first INV temperature sensor 76 detects a temperature of the first inverter 16, for example, a temperature associated with the switching elements. The second INV temperature sensor 77 detects a temperature of the second inverter 17, for example, a temperature related to the switching element. The catalyst temperature sensor 78 detects the temperature of the aftertreatment device 57. The turbine temperature sensor 79 detects the temperature of the turbine 53. The brake pedal stroke sensor 91 detects the depression amount of the brake pedal. The steering angle sensor 92 detects a steering angle (i.e., a rotation angle of a steering wheel). The G sensor detects acceleration in a predetermined direction (for example, a front-rear direction, a left-right direction, or an up-down direction) of the vehicle 10. Various sensors output signals indicating the detection results to the HV-ECU 62.

The sport mode selection switch 90 is an operation means for selecting a sport mode as one of control modes associated with responsiveness to an accelerator operation. The sporty mode may be, for example, a mode in which the required driving force for the accelerator position is higher than the required driving force for the same accelerator position when the sporty mode is not selected, or a mode in which an operation line higher in engine torque is selected as a predetermined operation line to be described later for the same engine speed as compared with the operation line when the sporty mode is not selected. The sport mode may also be selected, for example, in an EV travel mode or an HV travel mode described later. When the user operates the sport mode selection switch 90, a signal indicating the user operation is output from the sport mode selection switch 90 to the HV-ECU 62. When the HV-ECU62 receives the signal indicating the running from the sporty mode select switch 90, the HV-ECU62 sets the required driving force to be higher than the driving force when the sporty mode is not selected, or selects a higher running line in engine torque than when the sporty mode is not selected, as described above. When the sport mode is selected, the HV-ECU62 may turn on a flag (selection flag) indicating the selection of the sport mode.

The battery monitoring unit 73 acquires a state of charge (SOC) indicating a ratio of the remaining amount of the battery 18 to the full charge capacity, and outputs a signal indicating the acquired SOC to the HV-ECU 62.

The battery monitoring unit 73 includes, for example, sensors that detect the current, voltage, and temperature of the battery 18. The battery monitoring unit 73 obtains the SOC by calculating the SOC based on the detected current, voltage, and temperature of the battery 18.

As a method of calculating the SOC, various known methods such as a method by accumulating a current value (coulomb counting) or a method by estimating an Open Circuit Voltage (OCV) can be employed.

< control relating to travel of vehicle >

The vehicle 10 configured as above may be set or switched to a travel mode such as a Hybrid (HV) travel mode in which the engine 13 and the second MG 15 serve as power sources and an Electric (EV) travel mode in which the vehicle travels with the engine 13 kept stopped and the second MG 15 driven by electric power stored in the battery 18. Setting and switching to each mode are performed by the HV-ECU 62. The HV-ECU62 controls the engine 13, the first MG14, and the second MG 15 based on the set or switched running mode.

The EV running mode is selected, for example, in a low-load operation region where the vehicle speed is low and the required driving force is low, and refers to a running mode in which the operation of the engine 13 is stopped and the second MG 15 outputs the driving force.

The HV travel mode is selected in a high-load operation region where the vehicle speed is high and the required driving force is high, and refers to a travel mode that outputs a combined torque of the driving torque of the engine 13 and the driving torque of the second MG 15.

In the HV travel mode, the first MG14 applies a reaction force to the planetary gear mechanism 20 while transmitting the drive torque output from the engine 13 to the drive wheels 24. Therefore, the sun gear S functions as a reaction force element. In other words, in order to apply the engine torque to the drive wheels 24, the first MG14 is controlled to output a reaction torque against the engine torque. In this case, the regeneration control in which the first MG14 functions as a generator may be performed.

The following will describe the coordinated control of the engine 13, the first MG14, and the second MG 15 when the vehicle 10 is running.

The HV-ECU62 calculates the required driving force based on the accelerator position determined by the depression amount of the accelerator pedal. The HV-ECU62 calculates the required running power of the vehicle 10 based on the calculated required driving force and the vehicle speed. The HV-ECU62 calculates a value resulting from adding the required charging power and discharging power of the battery 18 to the required operating power as the required system power. For example, the required charging power and discharging power of the battery 18 are set according to the difference from the SOC of the battery 18 and a predetermined control center value.

The HV-ECU62 determines whether or not the start of the engine 13 has been requested based on the calculated required system power. For example, when the required system power exceeds a threshold, the HV-ECU62 determines that the start of the engine 13 has been requested. When the start of the engine 13 has been requested, the HV-ECU62 sets the HV running mode to the running mode. When the starting of the engine 13 is not required, the HV-ECU62 sets the EV running mode to the running mode.

When starting of the engine 13 has been requested (i.e., when the HV travel mode is set), the HV-ECU62 calculates a requested power of the engine 13 (hereinafter referred to as requested engine power). For example, the HV-ECU62 calculates the required system power as the required engine power. For example, when the required system power exceeds the upper limit value of the required engine power, the HV-ECU62 calculates the upper limit value of the required engine power as the required engine power. The HV-ECU62 outputs the calculated required engine power to the engine ECU 64 as an engine operating state command.

The engine ECU 64 sends a control signal C2 based on the engine operating state command input from the HV-ECU62, and controls various components of the engine 13, such as the intake throttle valve 49, the ignition plug 45, the wastegate valve 55, and the EGR valve 60, in various manners.

The HV-ECU62 sets an operating point of the engine 13 in a coordinate system defined by the engine speed and the engine torque based on the calculated required engine power. The HV-ECU62 sets, for example, an intersection between a line of equal power, which is equal in output to the required engine power in the coordinate system, and a predetermined operation line as an operation point of the engine 13.

The predetermined operation line represents a variation locus of the engine torque with the engine speed variation in the coordinate system, and is set by adjusting the engine torque variation locus of high fuel efficiency by experiment, for example.

The HV-ECU62 sets the engine speed corresponding to the set operating point to the target engine speed.

As the target engine speed is set, the HV-ECU62 sets the torque command value for the first MG14 for setting the current engine speed to the target engine speed. The HV-ECU62 sets a torque command value for the first MG14 by feedback control, for example, based on the difference between the current engine speed and the target engine speed.

The HV-ECU62 calculates the engine torque to be transmitted to the drive wheels 24 based on the set torque command value for the first MG14, and sets the command value for the second MG 15 so as to satisfy the required driving force. The HV-ECU62 outputs the set torque command values for the first MG14 and the second MG 15 to the MG-ECU 63 as a first MG torque command and a second MG torque command.

The MG-ECU 63 calculates a current value corresponding to the torque generated by the first MG14 and the second MG 15 and the frequency thereof based on the first MG torque command and the second MG torque command input from the HV-ECU62, and outputs a control signal C1 including the calculated current value and the frequency thereof to the PCU 81.

The HV-ECU62 also sends a control signal C3 to the EOP38 based on the operation state including the running mode, and controls the driving of the EOP 38.

For example, when the set operating point is in the supercharged intake region, the HV-ECU62 requests an increase in the supercharging pressure. In the present embodiment, the boundary between the supercharged intake region and the non-supercharged intake region (normal intake region) may be defined by a threshold value of the engine torque or by the engine torque and the engine speed. For example, when the boundary between the supercharged intake region and the non-supercharged intake region is defined by a threshold value of the engine torque, the HV-ECU62 may request an increase in the supercharging pressure when the engine torque corresponding to the set operating point exceeds the threshold value. Alternatively, when the boundary between the supercharged intake region and the non-supercharged intake region is defined by the engine torque and the engine speed, the HV-ECU62 may request an increase in the supercharging pressure when the engine speed and the engine torque corresponding to the set operating point reach values corresponding to values in the supercharged intake region.

Although fig. 3 shows a configuration in which the HV-ECU62, the MG-ECU 63, and the engine ECU 64 are separately provided by way of example, these ECUs may be integrated into a single ECU.

< relationship between accelerator operation and control of travel of vehicle >

For example, in the vehicle 10 including the turbocharger 47 configured as described above, when the operation to close the accelerator is performed with the HV running mode selected, the required power of the engine 13 is reduced or the engine 13 is stopped in response to the operation by the user from the viewpoint of improving the fuel efficiency. However, when the operation of opening the accelerator is performed again in a short time after the operation of closing the accelerator, there is a possibility that acceleration lag occurs due to a delay in response of the boost pressure. In particular, in the hybrid vehicle, as described above, the engine 13 may also be stopped by the operation of closing the accelerator. Therefore, when the operation of opening the accelerator is performed in a short time after the operation of closing the accelerator, a delay in acceleration may occur more significantly. Therefore, the drivability of the vehicle 10 may be deteriorated.

In the present embodiment, when the required engine power of the engine 13 is reduced in the supercharged intake region where the supercharged intake operation is performed by the turbocharger 47, the HV-ECU62 sets the upper limit value of the magnitude of change per prescribed period of the operating point to be smaller than the upper limit value of the magnitude of change per prescribed period of the operating point when the reduction in engine power is required in the non-supercharged intake region.

By so doing, for example, even when an operation to open the accelerator is performed within a short period of time after an operation to close the accelerator in the supercharged intake region, the change in the operating point is slower than the change in the operating point in the non-supercharged intake region. Therefore, the supercharging pressure can be maintained, and a quick stop of the engine 13 can be suppressed. Therefore, it is possible to suppress the occurrence of acceleration lag due to a response delay of the boost pressure. Therefore, deterioration of the drivability of the vehicle 10 can be suppressed.

< regarding the processing executed by the HV-ECU62 >

The processing executed by the HV-ECU62 will be described below with reference to FIG. 4. Fig. 4 is a flowchart showing exemplary processing executed by the HV-ECU 62.

In step (step denoted as S below) 100, the HV-ECU62 calculates the required system power.

In S102, the HV-ECU62 determines whether a request to start the engine 13 has been issued. When it is determined that the request to start the engine 13 has been issued (yes in S102), the process proceeds to S104.

In S104, the HV-ECU62 calculates the required engine power. The HV-ECU62 calculates the required system power as the required engine power, for example.

Since the method of calculating the required system power, the method of determining the start request of the engine 13, and the method of calculating the required engine power are as described above, detailed descriptions thereof will not be repeated.

In S106, the HV-ECU62 sets an operating point on a predetermined operating line. Specifically, the HV-ECU62 sets, as an operation point, an intersection between an equal power line that requires engine power and a predetermined operation line. Since the isopower line and the predetermined operation line are as described above, detailed description thereof will not be repeated.

In S108, the HV-ECU62 determines whether the vehicle is in a moving running state. For example, when the sport running mode is selected, the HV-ECU62 determines that the vehicle 10 is in a sport running state. For example, when the selection flag is on, the HV-ECU62 may determine that the vehicle is in a moving running state. When it is determined that the vehicle is in the moving running state (yes in S108), the process proceeds to S110.

In S110, the HV-ECU62 determines whether the previous operating point is within the supercharged intake region. For example, in an example in which the boundary between the supercharged intake region and the non-supercharged intake region is defined by a threshold value of the engine torque, the HV-ECU62 may determine that the previous operating point is in the supercharged intake region when the engine torque corresponding to the previous operating point is higher than the threshold value. Alternatively, in an example in which the boundary between the supercharged intake region and the non-supercharged intake region is defined by the engine torque and the engine revolution number, the HV-ECU may determine that the previous operating point is in the supercharged intake region when the previous operating point is located on one side of the supercharged intake region with respect to the boundary defined by the engine torque and the engine revolution number. When it is determined that the previous operating point is in the supercharged intake region (yes in S110), the process proceeds to S112.

In S112, the HV-ECU62 sets the first value as the upper limit value of the magnitude of the decrease in the engine speed. The first value is, for example, a predetermined value and is an upper limit value of the magnitude of the reduction amount of the engine speed corresponding to the sporty running state. The first value is smaller than a second value that represents an upper limit value of the magnitude of the decrease amount of the engine speed corresponding to a state other than a sporty running state described later. The first value is set such that the decrease in the engine speed is slower than the decrease in the engine speed when the second value is set.

When it is determined that the vehicle is not in the moving running state (no in S108), or when it is determined that the change in the operation point is not changed within the supercharged intake region (no in S110), the process proceeds to S114.

In S114, the HV-ECU62 sets the second value as the upper limit value of the magnitude of the decrease in the engine speed. The second value is, for example, a predetermined value, and is an upper limit value of the magnitude of the decrease amount of the engine speed corresponding to a state other than the sporty running state as described above. The second value should be only greater than the first value and is not particularly limited.

In S116, the HV-ECU62 corrects the operating point set in S106 using the set upper limit value. For example, when the magnitude of the decrease in the engine speed in the change from the previous operating point to the current operating point exceeds the upper limit value, the HV-ECU62 sets the position of the upper limit value on the predetermined operating line that is lower than the previous operating point by the magnitude of the decrease in the engine speed, as the corrected operating point, and when the magnitude of the decrease in the engine speed in the change from the previous operating point to the current operating point is equal to or less than the upper limit value, the HV-ECU62 sets the current operating point as the corrected operating point.

In S118, the HV-ECU62 outputs an engine operating state command. Specifically, the HV-ECU62 generates an engine operating state command in such a manner that the engine power corresponding to the corrected operating point is defined as the required engine power, and outputs the engine operating state command to the engine ECU 64. When it is determined that the request to start the engine 13 has not been issued (no in S102), the process proceeds to S120.

In S120, the HV-ECU62 outputs a first MG torque command. Specifically, the HV-ECU62 sets the engine speed corresponding to the corrected operating point as the target engine speed. The HV-ECU62 sets a torque command value for the first MG14 to set the current engine speed to the set target engine speed. The HV-ECU62 outputs the set torque command value for the first MG14 to the MG-ECU 63 as a first MG torque command.

In S122, the HV-ECU62 outputs a second MG torque command. Specifically, the HV-ECU62 calculates the engine torque to be transmitted to the drive wheels 24 based on the torque command value from the first MG14 and the gear ratio of each rotating element of the planetary gear mechanism 20, and sets the torque command value for the second MG 15 so as to achieve the required driving force. The HV-ECU62 outputs the set torque command value for the second MG 15 to the MG-ECU 63 as a second MG torque command.

When the request to start the engine 13 has not been issued, the HV-ECU62 sets the torque command value of the second MG 15 so that the second MG 15 alone generates the required driving force.

< regarding exemplary operations performed by the HV-ECU62 >

The operation of the HV-ECU62 according to the present embodiment based on the above-described structure and flowchart will be described with reference to FIG. 5. Fig. 5 is a diagram for explaining an exemplary operation performed by the HV-ECU 62. The ordinate in fig. 5 represents the engine torque. The abscissa in fig. 5 represents the engine speed. Fig. 5 shows a predetermined running line LN1 (solid line) corresponding to the sport running mode. Fig. 5 shows an equal power line (dashed line) of the (exemplary) demanded engine power LN 2. It is assumed that the boundary between the supercharged intake region and the non-supercharged intake region is defined by the threshold value Ta of the engine torque. Assume that an example of a sporty driving mode has been selected (i.e., an example of a selection flag being on).

For example, point B is assumed to be the previous operating point. At point B, the engine speed reaches Ne (4), and the engine torque reaches Te (4).

For example, when an operation of closing the accelerator is performed, a required system power according to the accelerator position is calculated (S100). When it is determined that the request for starting the engine 13 has been issued because the calculated requested system power has exceeded the threshold value (yes in S102), the requested engine power is calculated (S104), and an operating point is set on a predetermined operating line (S106). An intersection a between a predetermined operation line (LN 1 in fig. 5) and a line of equal power (LN 2 in fig. 5) that requires engine power is set as an operation point. At the intersection a, the engine rotational speed reaches Ne (2), and the engine torque reaches Te (2).

Since the select flag is on and the previous operating point (point B) is determined to be in the supercharging intake region (yes in S110), it is determined that the vehicle is in the moving travel state (yes in S108). Therefore, the first value is set as the upper limit value of the magnitude of the decrease in the engine speed (S112). The magnitude of the first value is equal to the magnitude from Ne (4) to Ne (3).

When changing from the previous operating point (point B) to the current operating point (point a), the engine rotational speed decreases from Ne (4) to Ne (2). Since the magnitude of the decrease amount exceeds the upper limit value (first value), a point C on the predetermined operation line is set as the operation point after the correction, at which the engine speed is lower than the previous operation point (point B) by the upper limit value of the decrease amount of the engine speed (S116). At point C, the engine speed reaches Ne (3), and the engine torque reaches Te (3).

In the case where the engine power corresponding to point C as the operating point is defined as the required engine power, the engine operating state command is output to engine ECU 64 (S118).

Then, the first MG torque command corresponding to the point C defined as the operation point is output to the MG-ECU 63(S120), and the second MG torque command is output to the MG-ECU 63 (S122). Therefore, a decrease in engine torque is suppressed, and the operating point is maintained within the supercharged intake region. Therefore, the supercharged intake state of the supercharged intake by the turbocharger 47 is maintained.

On the other hand, point D in the non-supercharged intake region is assumed as the previous operating point. At point D, the engine speed reaches Ne (1), and the engine torque reaches Te (1).

For example, when an operation of closing the accelerator is performed, a required system power according to the accelerator position is calculated (S100). When it is determined that a request for starting the engine 13 has been issued because the calculated required system power has exceeded the threshold value (yes in S102), a required engine power is calculated (S104), and an operating point is set on a predetermined operating line (S106). At this time, the intersection E is set as the operating point. At point E, the engine speed reaches Ne (0), and the engine torque reaches Te (0).

Although it is determined that the vehicle is in the moving running state due to the selection flag being on (yes in S108), it is determined that the previous operation point (point D) is not within the supercharging intake region (no in S110). Therefore, the second value is set as the upper limit value of the magnitude of the decrease amount of the engine speed (S114). The second value is assumed to be greater than the first value and greater than a magnitude from Ne (4) to Ne (2).

When changing from the previous operating point (point D) to the current operating point (point E), the engine rotational speed decreases from Ne (1) to Ne (0). The magnitude of the amount of decrease is assumed to be equal to the magnitude of the amount of decrease from Ne (4) to Ne (2). Since the magnitude of the decrease amount does not exceed the upper limit value (second value), the point E is set as the corrected operation point (S116).

In the case where the engine power corresponding to point E as the operating point is defined as the required engine power, the engine operating state command is output to engine ECU 64 (S118).

Then, the first MG torque command corresponding to the point E defined as the operation point is output to the MG-ECU 63(S120), and the second MG torque command is output to the MG-ECU 63 (S122).

< function and Effect >

As described above, according to the hybrid vehicle in the embodiment, for example, even when the operation to turn on the accelerator is performed within a short period of time after the operation to turn off the accelerator in the supercharged intake region when the sporty running mode in which no importance is placed on the user for improving the fuel efficiency is selected, the change of the operating point (in particular, the decrease of the engine speed) is slower than that in the non-supercharged intake region. Therefore, the boost pressure can be maintained, and a quick stop of the engine 13 can be suppressed. Therefore, it is possible to suppress the occurrence of acceleration lag due to a response delay of the boost pressure. Therefore, deterioration of the drivability of the vehicle 10 can be suppressed. Therefore, it is possible to provide a hybrid vehicle and a method of controlling the hybrid vehicle in which the occurrence of acceleration lag is suppressed due to a response delay of the boost pressure.

< modifications >

The modifications will be described below.

Although the intake throttle valve 49 is described as being disposed between the intercooler 51 and the intake manifold 46 in the above embodiment, it may be disposed, for example, in the intake passage 41 between the compressor 48 and the airflow meter 50.

Although the boost pressure is adjusted by adjusting the position of the wastegate valve according to the description of the above-described embodiment, the boost pressure may be adjusted, for example, by providing a motor generator in a shaft that connects the compressor 48 and the turbine 53 to each other and controlling the turbine rotation speed by the motor generator, or may be adjusted by adjusting the gap (blade position) between adjacent blades of a plurality of blades arranged around the outer periphery of the blades of the turbine 53.

Although according to the description of the above-described embodiment, the upper limit value of the magnitude of the decrease in the engine rotational speed is set, only the upper limit value of the magnitude of the change in the operating point should be set, and for example, the upper limit value of the magnitude of the decrease in the engine torque may be set instead of the upper limit value of the magnitude of the engine rotational speed, or the upper limit value of the magnitude of the decrease in the engine power may be set.

Although it is determined that the vehicle 10 is in the sport running state when the sport running mode has been selected according to the description of the above embodiment, it may be determined whether the vehicle 10 is in the sport running state based on the running record, for example. For example, the HV-ECU62 may determine that the vehicle 10 is in the sport running state when the rate of the duration in which the magnitude of the acceleration of the vehicle 10 detected by the G sensor 93 exceeds the threshold value within a predetermined time is equal to or higher than the threshold value. Alternatively, the HV-ECU62 may determine that the vehicle 10 is in the moving running state when the ratio of the duration during which the amount of change in the accelerator position exceeds the threshold value within the predetermined time is equal to or higher than the threshold value. Alternatively, the HV-ECU62 may determine that the vehicle 10 is in the moving running state when the rate of the duration in which the amount of change in the brake pedal stroke exceeds the threshold value within the prescribed period of time is equal to or higher than the threshold value. Alternatively, the HV-ECU62 may determine that the vehicle 10 is in the moving running state when the ratio of the duration during which the amount of change in the steering angle exceeds the threshold value within the prescribed period of time is equal to or higher than the threshold value.

Although the processing for setting the upper limit value (first value) of the magnitude of the reduction amount of the engine speed in the case where the previous operation point is within the supercharged intake region to be smaller than the upper limit value (second value) of the magnitude of the reduction amount of the engine speed in the case where the previous operation point is within the non-supercharged intake region is executed only when the vehicle 10 is in the sporty running state according to the description in the above embodiment, the processing may be executed regardless of whether the vehicle 10 is in the sporty running state. The process executed by the HV-ECU62 in this modification is the same as the process without the process in S108 in the flowchart of fig. 4, for example. Therefore, detailed description will not be repeated.

Although a turbocharger is described as an exemplary supercharged intake device in the above embodiment, for example, a supercharger that drives a compressor using the power of the engine 13 may be applied instead of the turbocharger 47.

The above-described modifications may be implemented in whole or in part in appropriate combinations.

While embodiments of the present invention have been described, it is to be understood that the embodiments disclosed herein are illustrative and not restrictive in every respect. The scope of the invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.